Hi, first post, fabia vrs problems!

Hi everyone, I have a fabia vrs tsi I bought new last year, and it has the dreaded oil consumption issues and has since new. Had to top up the oil all the time then Arnold Clark did the oil test and confirmed it needed the piston rings replaced.

So I was told it was a 3 day job, it's been 3 weeks and is still in bits in their workshop. Iv been told that first it needed other parts, then the master tech was on a course then he was off sick. Iv Been in this morning to see what's happening and was taken to see the car with all the parts laid on sheets beside it and was told it should be ready this week.

They have given me a courtesy car since it was taken in but where do I stand? Obviously the time scale is unacceptable but I'm also worried it won't be the same car when I get it back or that it won't be fixed? Could I push for a new engine or even reject the car if im not happy the problem has been sorted?